The present invention relates to a data input device to be coupled with a data processing device for use in automobiles.
Recently, automobiles are equipped with various devices such as a stereo receiver set and a digital clock, and one of most recently developed and handy devices for use in the automobile is a micro-computer or data processing unit which may be used for calculating the mileage of fuel by dividing the consumed fuel by the travelled distance or for calculating the distance of travel available with the remaining fuel by dividing the amount of remaining fuel by the mileage.
For calculating such amounts as described above, it is necessary to provide a data input device having a number of keys to pushed by the driver. Generally, for effecting the entry of the numeral data into the data processing device, a keyboard has ten keys respectively designating the decimal digits 0, 1, 2, . . . , and 9, which are selectively pushed by the operator. However, this type of data input device having ten keys for numeral data input has such disadvantages that: (i) the number of keys is too many for the driver to operate when he is driving the automobile; and (ii) the size of the keyboard becomes considerably large.